Electric regulator.



L. W. THOMPSON. ELECTRIC REGULATOR APPLICATION FILED FEB. 26, 1915.

1 ,209,5 1 8 Patented Dec. 19, 1916.

/W' Wm M by Atty: I

UNITED STATES PATENT OFFICE.

LOUIS WILLARD THOMPSON, OF NEW YORK, N. Y., ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC REGULATOR.

Specification of Letters Patent.

Patented Dec. 19, 1916.

Application filed February 26, 1915. Serial No. 10,695.

To all whom it may concern:

3e it known that I, LOUIS -WILLARD Tnonrson, a citizen'of the United States, and a resident of the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Electric Regulators, of which the following is a description, accompanied by drawings.

This invention relates to electric regulators, but more particularly to alternating current voltage regulators, for automatically maintaining the voltage of a generator by effecting momentary changes in the field of the generator, such changes being greater than those which would be required to restore the desired voltage if the changed condition in the field of the generator were continuously maintained.

In voltage regulators of this character, in which the momentary changes in the field of the generator are eifected in response to the generator voltage, the electrical and mechanical inertia. of the parts produces a fluctuation in the generator voltage much greater than the small fluctuation necessary to the operation of the field changing means. This condition, commonly known as hunting, is highly objectionable.

The primary object-of this invention is,

therefore, to provide a regulator which shall be substantially free from hunting. To this end means, to the operation of which fluctuations in the generator voltage are not essential, are employed to impart to the controlling memberof the field changing means a vibratory movement. The mcansto produce this vibratory movement comprise an alternating current circuit, including a low frequency source of alternating current and a Winding in operative relationwith said controlling member.

In the preferred form of the invention the regulator comprises a controlling solenoid responsive to the conditions of the circuit to be regulated, and an auxiliary solenoid which is energized from the source of loW frequency current. The auxiliary solenoid is continuously energized and serves to influence and modify the action of the main controlling solenoid, the energization of which varies with the conditions of the circuit to be regulated.

Obviously, various circuits and connections may be devised without departing tion to the apparatus shown and described,

which .is illustrative of a preferred form of the invention.

The drawing is a diagrammatic representation of circuits and apparatus for carrying out the invention.

Referring to the drawings, A represents an alternating current generator connected to the mains B, C, the voltage upon which is to be regulated. The field U of the alternator is excited by a direct current exciter D and the voltage of the mains B, C, is regulated by regulating the excitation. The voltage of the exciter D is varied, by varying the strength of its field E, in the circuit of which is shown an exeiter rheostat F. This rheostat F, as shown, may be short circuited by means of the contacts G and H controlled by suitable means actuated by the control solenoid J, which is responsive to the conditions of the circuit to be regulated by means of the leads K and L, through anon-inductive resistance R which is preferably inserted as usual in one of the leads,

and a solenoid V. The solenoidV is supplied with current of low frequency from the phase wound rotor Y of the induction motor TV by means of the slip rings cd and the leads ef. A variable resistance 1' is preferably connected across the leads ef. The stator windings XX of the induction motor W are connected to the leads K-L at the points a and Z). The frequency of thecurrent supplied to the solenoid V may be adjusted to the desired value by regulating the resistance 7 which varies the slip of the rotor Y.

The operation of the regulator is as follows: Assume the Voltage of the generator to have the desired value. The core 0 Will be vibrated by reason of the current of low frequency supplied to the coil V, and will cause the contacts GH to be alternately opened and closed, and the relative periods during which said contacts are ens disengaged will he such suhstairtiallj' no change in the Voltage of the generator 13 eliected by reason of he alternate engageof this vibration, which will he oi suhstarn tially the same amplitude and frequency as before, will be displaced from the range of the yi bration in the first instance With-the result that the contacts G and in.

engagement for a shorter portion of eachv vibration. 'lllns results in a decrease in the voltage of the generator. Similarly, if the voltage of the generator falls below the sired value, the vibration the core 0 u have the some amplitude and frequency before, but the range of its vibration will be displaced from the range of vibration in the previously mentioned instances, with the result that the contacts and ll will he in engagement duringa greater portion of the vibration of said core than when the voltage of the generator has the desired value. This results in an increase in the voltage of the generator.

The use of the coil V prevents hunting, since it is not necessary to the periodic gagement of the contacts G and H that t -e strength of the solenoid J, and consequently the voltage across the mains B-C, snould vary. By the cooperation of the solenoids J and V, energized from their respective sources, the voltage of the generator ll. is maintained substantially constant and a tendency to hunting? is avoided.

I claim and desire to obtain by Letters lPatc-nt the follovvingz--- 1. The combination With an alternating current circuit to be regulated, of a regulator comprising electro-responsive means tosponsive to a departure from a desired cir cuit condition, for restoring said desired. condition, and means for constantly subjecting said clcctroresponsive means to an alternating current of very low frequency com pared to the frequency of the circuit to be regulated.

2. The combination with an alternating current circuit to be regulated. of a regula' tor comprising electro-responsive means re-- sponsive to a departure from a desired. circuitcondition, for restoring said desired condition, and means for continuously subjecting said electro-responsive means to substantially constant alternating current of lower frequency than that of. the circuit to be regulated,

3. The combination with an alternating current circuit to he regulated, of reg l1.-

tor comprising clectro-responsive means re sponsive to departure from a desired circuit condition, for restoring said desired condition, a constantly operative source of current of lower frequency than that of circuit to he renjula" and connections for continuously impres said low 'lrcmiency current upon the said electro-respousive regl'llating means, and thereby inl'luencing and modifying the action of said electrorcsponsive means.

4.. The combination. with an electric circuit to be regulated, of a regulator comprising a fixed contact, a movable contact associated therewith, a coil responsive to an electrical condition of said circuit, a core for said coil controlling said. movable contact, and electromagnetic means, the control which is independent of the regulator,

or continuously imparting 'a vibratory erce to said core. 7

In a regulator, the C(Jl'l'llllllilhlfill of an elcctro-responsive device, means :l'or impressing variable alternating current of a given frequency upon said device, means for continuously impressing a substantially constant alternating current of lower frequency upon said device, and regulating means con trolled by said device,

6. The combination with an alternating current circuit to be regulated, of a regular tor comprising; a controlling magnet respon we to the voltage of the circuit to he regulatcd, and a source of current of lower frequenc than that of the circuit to he regulated, for altering the restoring power of sai d ma 7 The combination. with an. alternating current circuit to be regulated, of regulator responsive to electrical conditions i said circuit, and a continuously acting; source of current of lower frequency than that of the circuit to be regulated, for modifying the action of said regulator when the cond'tion of the circuit approaches desired, whereby hunting is prevented.

8. The combination with an alternating current generator having lield, ol. a resistance affecting the strength of said. field, contacts opening and closing to insert and withdraw said resistance, means-responsive to variations of voltage of generator from a desired value for opening clco ing said contacts, said resistance h'eing greater than that which Would he required to effect the required change in. Voltage it continuously applied, and a source of alter-- noting current of l were frequency than the said generator continuously acting on said contact opening and closi. means "for modifying the action of said means When the voltage of the generator approaches the desired value, whereby hunting is pre vented.

9. The combination With an alternating circuit to he regulated, of electroing an electromagnet responsive responsive means, responsive both to the condition in said circuit and to an alternating current of relatively lower frequency than the frequency of said circuit, for maintaining a desired condition in said circuit.

10. In a system of regulation for an alternating current generator, the combination with the generator of a regulator compristo the gen.- erator voltage, means operated by said electromagnet for controlling the generator voltage, and a circuit-including a low frequency source of alternating current cooperating With said means to modify the action thereof.

1;. In a system of regulation for an alter nat-lng current generator, the combination with the generator of a regulator comprising an electromagnet responsive to the generator voltage, means operated by said electromagnet for controlling the generator .voltage, and a circuit including a Winding and a low frequency of said electromagnet source of alternating current to action of said means.

12. In a system of regulation'for an alternating current generator, the combination with the generator of a regulator comprising an electromagnet responsive to the generator voltage, means operated by said electromagnet for controlling the generator voitage, an induction motor having a phase wound secondary adapted to be driven from said generator, and a circuit including a winding of said electromagnet and the secondary of said induction motor to modify the action of said means, and means to vary the relative speeds of the primary and secondary of said induction motor.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

LOUIS WILLARD THOMPSON. Witnesses l VALTER S. JoNns,

HERBERT G. ()GDEN.

modify the 

